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Diabetic Macular Edema (DME) Fact Sheet

Approximately 26 million people in the U.S. have diabetes.1 People
with diabetes are at an increased risk for developing eye problems. One reason is because
diabetes and other complications can cause damage to the blood vessels of the retina (diabetic
retinopathy).

Diabetic macular edema (DME) is a serious eye condition that affects people with diabetes (type 1
or type 2). "Macular" refers to the macula, which is the central portion of the retina and the
part of the eye responsible for sharp central vision.2 Edema means
swelling of tissues from fluid.

DME results when the damaged blood vessels leak fluid and cause swelling, which blurs vision. If
retinopathy worsens, the eye may begin to form new, abnormal blood vessels over the retina,
which can break easily and bleed, causing severe vision loss and even blindness.2,3,4
DME can occur at any stage of diabetic retinopathy, although it is more likely to occur
as the disease progresses.2

Types of DME

DME can be broadly characterized into two main anatomic categories - Focal and Diffuse:

Focal DME is characterized by specific areas of separate and distinct leakage in the
macula with sufficient macular blood flow.4

Diffuse DME results from leakage of the entire capillary bed surrounding the macula,
resulting from a breakdown of the inner blood-retina barrier of the eye.5

In addition to Focal and Diffuse, DME is also categorized based on clinical exam findings
into clinically significant macular edema (CSME), non-CSME and CSME with central involvement
(CSME-CI), which involves the fovea.

Prevalence of DME

DME is a leading cause of vision loss among the working-age population of most developed
countries.6

Approximately 70 percent of patients with the most severe form of diabetic retinopathy,
proliferative retinopathy, will develop DME.5

Symptoms and Diagnosis of DME

Symptoms of DME include blurred vision, double vision, loss of contrast and floaters patches
of vision loss, which may appear as small black dots or lines "floating" across the front of
the eye.2

In order to diagnose diabetic macular edema, a physician will perform a comprehensive eye
exam that includes: a visual acuity test, which determines the smallest letters a person can
read on a standardized chart, a dilated eye exam in which drops are placed in the eyes to
widen the pupils in order to check for signs of the disease, imaging tests such as optical
coherence tomography (OCT) or fluorescein angiography (FA) and tonometry, an instrument that
measures pressure inside the eye.2

DME Risk Factors

The risk for developing DME is closely associated with the length of time a patient has
lived with diabetes and the severity of diabetic retinopathy.2,3 Poor control of blood sugar
also increases the risk of developing DME.8

8 Diabetes Control and Complications Trial/Epidemiology of Diabetes
Interventions and Complications Research Group. Retinopathy and nephropathy in
patients with type 1 diabetes four years after a trial of intensive therapy. The New
England Journal of Medicine. 2000; 342:381-389.